Grant: Discovery Grants Program - Individual

Organisms live in an uncertain and challenging world in which the critical measure of success (fitness) is the number of progeny they produce that subsequently also reproduce. Processes operating during the breeding cycle can especially influence fitness. In birds, for example, choice of an appropriate mate, allocation of energy and nutrients to offspring, and external factors such as levels of parasitism are all critical. To better understand why fitness varies among individuals, my research will focus on two major areas of study: (1) Indicators of Quality in Birds: In males of many bird species, elaborate ornaments such as bright plumage are indicators of the quality of individuals, and females base their mate choice decisions on the degree to which these traits are expressed. Many female birds also display elaborate plumage, but whether such traits indicate quality or are used by males to choose some females over others is not clear. My studies will investigate relationships between plumage colour and quality of female birds, and experiments will be conducted to determine whether female colour expression influences mating behaviour. I will also use experiments to investigate how previous reproductive effort (stress) affects the ability of females to develop bright plumage, and how conditions experienced by offspring in the nest subsequently influence colour expression as adults. (2) Nest-dwelling ectoparasites can have detrimental effects on offspring growth and survival, yet we know little about how these parasites are able to locate nests, and what influences which chick is exploited within a nest. I will test the role of various chemical cues in facilitating nest location by parasitic blow flies, and will manipulate size hierarchies and immune function of chicks within nests to test how offspring quality influences selection of individual hosts by parasites. This research program will provide new and significant insights into the expression of phenotypic indicators of quality and the dynamics of host-parasite interactions, while providing rich opportunities for students to contribute to solving these critically important questions in evolutionary ecology and basic biology.